A large number of cylinders are filled each year with gases of various kinds and properties. Before each cylinder is filled, certain pre-fill inspections must be completed. The inspections should include at least a visual inspection to locate gouges, dents, burn marks, and discoloration, a sniff test to identify possible contaminants, a dead ring test to gauge the structural integrity of the cylinder, and a liquid check to detect the accumulation of liquids within the cylinder.
U.S. Patent Application Publication 2004/0194980 A1 discloses an apparatus for remote inspection of fluid containers having an electronic circuit in communication between each container and a remote central station. The electronic circuit is adapted to issue a wireless signal to the remote central station upon detection of pre-determined internal conditions, such as an out-of-range pressure condition of fluid contained within the volume of the container, or upon detection of predetermined external conditions, such as the lack of presence of the container in its installed position or the presence of an obstruction to viewing of or access to the container.
All industrial gas suppliers have pre-fill inspections that are performed prior to the filling of a cylinder. These pre-fill inspections are typically performed manually and therefore are time consuming and are often error-prone since they require subjective judgment. It would be desirable to reduce the time required to perform the pre-fill cylinder inspections thereby resulting in considerable cost savings.
It would also be desirable to identify with high reliability cylinders that are structurally unfit to be filled with high pressure gas. The structural integrity of all cylinders degrades over time with use, so reliably detecting the cylinders that are unfit to be filled can avoid a cylinder bursting, which could result in injury or death. In addition to natural degradation, an ongoing problem is that of human tampering with cylinders. One problem in packaged gas operations is the appearance of cylinders that have been altered to facilitate the drug trade. For example, on occasion cylinders have been found that were cut open and the porous mass removed so that the cylinder could be used to transport drugs. There has also been a recent surfacing of cylinders that have been tampered with for other purposes.
Removing the cylinder inspection errors that result from the subjective judgment of an operator/inspector can have a positive impact on operator/inspector safety because more defects are likely to be identified. It would be desirable to provide an apparatus and method for quickly and accurately determining if a cylinder is fit to remain in service. It would further be desirable to provide information to an operator/inspector that will help point out the type of defect, its location, and its severity.